1. Field of the Invention
The invention relates to the field of hand tools and, in particular, to a tool to install and remove the valves springs from the heads of overhead valve internal combustion engines.
2. Description of Related Art
A typical valve for an internal combustion engine includes a valve face and a stem that has a notched end. The valve springs are positioned about the valve stem with a cap placed thereover. The valve springs are held under a compression load by a split ring retainer (valve keeper) mounted between a recess in the cap and the underside of the notch. Thus in order to install or remove the valve springs, the springs must be further compressed so that the retainer can be removed.
Since the inception or the internal combustion engine there have been numerous tools developed to aid in the removal of the valve spring. For example U.S. Pat. No. 1,052,941, "Tool For Compressing Valve Springs" by C. Nyberg discloses a simple pliers with forked jaws that can be wedged "under" the ends of the valve spring and then closed to compress the spring. The main disadvantage of this simple device is that it would be difficult to insert about a heavy duty valve spring. Additionally, and although valve springs are made of high strength material, it is possible to damage the spring.
U.S. Pat. No. 1,370,397, "Valve Remover" by C. M. Axelton discloses a lever having a handle on one end, an opposite end terminating in a fork like member, and an aperture located therebetween. In operation, the forked end is attached to the head by means of a hook with the aperture aligned with the valve stem. The lever is thereafter rotated about the forked end compressing the valve spring. This causes the valve stem to extend through the aperture allowing the valve spring keeper to be removed. The problem with this particular device is that it must be physically secured to the head making its use a somewhat time consuming operation. U.S. Pat. No. 1,429,000, "Valve Spring Compressor" by P. L. Varble discloses a tool for removing valves from "flat head" engines wherein the valves are located in the side of the engine block. It is a simple "reverse clamp" type pliers wherein one jaw is positioned on the side of the engine block for support (on the edge of the recess for the push rod/valve spring assemblies) and the other jaw is inserted under the valve spring. Compressing the handles in this reverse clamp causes the jaws to move apart compressing the valve spring. The main limitation of this device is that it is only useful on "flat head" engines.
An improvement to the Varble device can be found in U.S. Pat. No. 1,607,153 "Spring Compressor And Carrier Holding Tool" by D. C. Feather in that it can be used for both overhead valve and flat head engines. Feather discloses a simple position locking pliers wherein lever arms replace the typical jaws. Separate jaws are pivotally attached to the handles and also engage the lever arms. Thus the jaws can be inserted about the valve spring whereafter the "closing" of the lever arms causes the jaws to compress the valve spring. However this device requires that at least one of the jaws be jammed into the spring that may cause damage thereto. U.S. Pat. No. 1,928,219 "Compression Type Valve Tool" by A. E. Church discloses an improvement to the Feather design in that interchangeable jaws are provided allowing the tool to be used with a wide variety of engine designs.
U.S. Pat. No. 1,908,785, "Valve Spring compressor" by W. F. Pioch and U.S. Pat. No. 1,924,246 "Spring Compressor" by H. W. Kulp, et al, U.S. Pat. No. 2,519,024, "Overhead Valve Spring Remover" by H. E. Collett just disclose over-center type locking pliers with forked shape jaws that function in a conventional manner.
Finally, U.S. Pat. No. 3,363,302, "Valve Spring Tool Device" by R. D. Haselmo, et al. is a lever type device which can be used with overhead valve engines that have rocker arm mounting studs in proximity to the valve. The Haselmo, et al. device is a flat lever having a forked first end, an actuation arm at the second end, and an aperture therebetween. The lever arm is positioned so that the forked end engages the valve spring and is thereafter secured to the head by placing the lever arm over the mounting stud so that the stud extends through the oversize aperture. A threaded nut is used to secure it thereto. With the aperture being oversize, the lever can be rotated about the stud causing the forked end to compress the valve spring. This device has the distinct disadvantage of requiring the time consuming step of attaching the device to the head prior to removal of the valve spring and it does not lock the valve spring in the compressed position.
Thus, it is a primary object of the invention to provide a tool for the installation and removal of valve springs from internal combustion engines.
It is another primary object of the invention to provide a tool for the installation and removal of valve springs from internal combustion engines having overhead valves.
It is a further object of the invention to provide a tool for the installation and removal of valve springs from internal combustion engines having overhead valves that does not require clamping or otherwise fastening the device to the engine.
It is a still further object of the invention to provide a tool for the installation and removal of valve springs from internal combustion engines having overhead valves that can lock the valve spring in a compressed position so as to allow easy removal of the valve keeper.